272 
REPORT ON ZOOLOGY, MDCCCXLII : 
his being acquainted with what had been done on this point by German 
Zoologists. 
Kroyer has given, in his monograph on the northern species of Hip- 
polyte^ his observations on the development of Hippolyte, Homarus, 
and Cymopolia. The embryo of Cymop. Caronii is distinguished from 
the embryo of other Brachyura, as only the hindmost pair of the tho- 
racic members project externally. (Dorsal and frontal spines first 
show themselves after the first exuviation.) The representation of the 
embryo of the lobster agrees essentially with that of Rathke. The 
young of Hippolyte polaris have very large sessile eyes, inclining 
towards each other; the antennae placed under the eyes, the inner 
being three-jointed, the outer six-jointed, and with a two-jointed leaf- 
like appendage ; the foot-jaws are cleft, the outer branch of the second 
and both branches of the third pair elongated ; the ambulatory feet short 
and simple ; the members of the swimming-tail consist of one common 
basal joint and two leaflets. 
Joly (Instit. p. 239 ; Rev. Zool. p. 229) has observed the young of 
Hypolyte Desmarestii, which, as they come from the egg, have schizo- 
podous feet, like those of My sis ; the front divided, a shovel-formed tail, 
no caudal members, three pair of thoracic feet, very large sessile eyes, 
unjointed antennal processes, and no gills. He could not completely 
distinguish the formation of the mouth in the little animal, at most 
2"' long, yet he distinguished the mandibles, two pair of perfectly de- 
veloped maxillae, and a single pair of foot-jaws. The young of this spe- 
cies evidently show many deviations from that observed by Kroyer, yet, 
in other respects, the H. Desmarestii difiers from the true Ilippolytes, 
It is a fortunate circumstance, that observations on the development of 
the Decapoda, which is so various, are thus increasing. 
The Decapoda of Ireland have been enumerated, and a list furnished, 
accompanied by valuable remarks on their distribution, by W. Thompson 
(Ann. Nat. Hist. x. p. 274). The part of this enumeration before me 
contains the Brachyura. 
Parthenopii. — Milne Edwards and Lucas (Archiv. du Mus. d’Hist. 
Nat. ii. p. 479, t. 28) have made known two new species, one of which 
forms a new genus, called Eurynolamhrus, because it unites the charac- 
teristics of Eurynome and Lambrus. The carapace is strongly dilated 
at the sides, covering the second and third pairs of feet ; the basal joint 
of the external antennaB very large, anteriorly soldered to the front, the 
moveable portion inserted beside the groove of the internal antennas : 
the species, E. australis, is from New Zealand. The other. Cryptopodia 
angulosa, native country unknown, is distinguished from the Cr. forni- 
cata, by the crenated margins of the carapace. 
Grapsoidei. — One new species, Grapsus strigilatus, Adam White 
(Gray Zool. Misc. ii. p. 78), from New Zealand, is allied to Gr. varius. 
316 
